Thin-film magnetic head with coil-insulating layer that thermal expansion coefficient and young'S modulus are specified

Abstract

A thin-film magnetic head which suppresses the TPTP phenomenon due to the environment temperature is provided. The thin-film magnetic head includes, an electromagnetic coil element having a coil layer and coil-insulating layer, and an overcoat layer. A width of the coil-insulating layer in a track-width direction is larger than a width that is needed to insulate the whole coil layer, and is at least 46 μm, and a length of the coil-insulating layer in a direction perpendicular to the track-width direction is larger than a length that is needed to insulate the whole coil layer, and is at least 75 μm. In addition, a heat expansion coefficient of the coil-insulating layer is larger than or equal to 30×10 −6 /K, and a Young's modulus of the coil-insulating layer is larger than or equal to 1 GPa and smaller than or equal to 4 GPa.

1. A thin-film magnetic head comprising:
 an electromagnetic coil element for writing data including a coil layer which generates a magnetic field by current flowing through the coil layer and a coil-insulating layer which surrounds the coil layer; and 
 an overcoat layer which covers the electromagnetic coil element, 
 a width in a track-width direction of the coil-insulating layer being larger than a width that is a minimum width needed to insulate the whole coil layer, and being at least 46 μm, 
 a length in a direction perpendicular to the track-width direction of the coil-insulating layer being larger than a length that is a minimum length needed to insulate the whole coil layer, and being at least 75 μm, 
 a heat expansion coefficient of the coil-insulating layer being larger than or equal to 30×10 −6 /K, 
 a Young's modulus of the coil-insulating layer being larger than or equal to 1 GPa and smaller than or equal to 4 GPa, and 
 the length of the coil-insulating layer is greater than the width of the coil-insulating layer. 
 
     
     
       2. The thin-film magnetic head as claimed in  claim 1 , wherein the heat expansion coefficient of said coil-insulating layer is larger than or equal to 60×10 −6 /K. 
     
     
       3. The thin-film magnetic head as claimed in  claim 1 , wherein said coil layer has a two layered structure, and said coil-insulating layer has a two layered structure. 
     
     
       4. The thin-film magnetic head as claimed in  claim 1 , wherein
 said electromagnetic coil element further includes
 a lower magnetic pole layer, and 
 an upper magnetic pole layer which sandwiches a write gap layer with said lower magnetic pole layer on an end portion on an air bearing surface side; 
 
 said coil layer is a write coil layer passing between said lower magnetic pole layer and said upper magnetic pole layer, the write coil layer generates a write magnetic field; and 
 said coil-insulating layer is a write coil-insulating layer which surrounds said write coil layer. 
 
     
     
       5. The thin-film magnetic head as claimed in  claim 1 , wherein
 said electromagnetic coil element further includes
 a main magnetic pole layer, 
 an auxiliary magnetic pole layer having an end on an air bearing surface side opposed to an end on the air bearing surface side of the main magnetic pole layer via a gap layer, 
 a backing coil layer formed on an area except the area between said main magnetic pole layer and said auxiliary magnetic pole layer, the backing coil layer having a coil surface parallel to a coil surface of a write coil layer, and 
 a backing coil-insulating layer which surrounds said backing coil layer; 
 
 said coil layer is the write coil layer which passes between said main magnetic pole layer and said auxiliary magnetic pole layer, the write coil layer generates a write magnetic field; and 
 said coil-insulating layer is a write coil-insulating layer which surrounds said write coil layer. 
 
     
     
       6. The thin-film magnetic head as claimed in  claim 1 , wherein
 said electromagnetic coil element further includes
 a main magnetic pole layer, 
 an auxiliary magnetic pole layer having an end on an air bearing surface side opposed to an end on the air bearing surface side of the main magnetic pole layer via a gap layer, 
 a write coil layer passing between said main magnetic pole layer and said auxiliary magnetic pole layer, the write coil layer generates a write magnetic field, and 
 a write coil-insulating layer which surrounds said write coil layer; 
 
 said coil layer is a backing coil layer formed on an area except the area between said main magnetic pole layer and said auxiliary magnetic pole layer, the backing coil layer having a coil surface parallel to a coil surface of a write coil layer; and 
 said coil-insulating layer is a backing coil-insulating layer which surrounds said backing coil layer. 
 
     
     
       7. The thin-film magnetic head as claimed in  claim 1 , further comprising: at least one heating portion for protruding an end on an air bearing surface side of said electromagnetic coil element toward a magnetic recording medium by a heat expansion. 
     
     
       8. The thin-film magnetic head as claimed in  claim 7 , further comprising: a magnetoresistive effect element for reading data, said heating portion being set between said magnetoresistive effect element and said electromagnetic coil element. 
     
     
       9. A head gimbal assembly comprising:
 a thin-film magnetic head including:
 an electromagnetic coil element for writing data including a coil layer which generates a magnetic field by current flowing through the coil layer and a coil-insulating layer which surrounds the coil layer; and 
 an overcoat layer which covers the electromagnetic coil element, 
 a width in a track-width direction of the coil-insulating layer being larger than a width that is a minimum width needed to insulate the whole coil layer, and being at least 46 μm, 
 a length in a direction perpendicular to the track-width direction of the coil-insulating layer being larger than a length that is a minimum length needed to insulate the whole coil layer, and being at least 75 μm, 
 a heat expansion coefficient of the coil-insulating layer being larger than or equal to 30×10 −6 /K, 
 a Young's modulus of the coil-insulating layer being larger than or equal to 1 GPa and smaller than or equal to 4 GPa, and 
 the length of the coil-insulating layer being greater than the width of the coil-insulating layer; and 
 
 a support mechanism for supporting said thin-film magnetic head. 
 
     
     
       10. The head gimbal assembly as claimed in  claim 9 , wherein said heat expansion coefficient of said coil-insulating layer is larger than or equal to 60×10 −6 /K. 
     
     
       11. The head gimbal assembly as claimed in  claim 9 , wherein said coil layer has a two layered structure, and said coil-insulating layer has a two layered structure. 
     
     
       12. The head gimbal assembly as claimed in  claim 9 , wherein
 said electromagnetic coil element further includes
 a lower magnetic pole layer, and 
 an upper magnetic pole layer which sandwiches a write gap layer with said lower magnetic pole layer on an end portion on an air bearing surface side; 
 
 said coil layer is a write coil layer passing between said lower magnetic pole layer and said upper magnetic pole layer, the write coil layer generates a write magnetic field; and 
 said coil-insulating layer is a write coil-insulating layer which surrounds said write coil layer. 
 
     
     
       13. The head gimbal assembly as claimed in  claim 9 , wherein
 said electromagnetic coil element further includes
 a main magnetic pole layer, 
 an auxiliary magnetic pole layer having an end on an air bearing surface side opposed to an end on the air bearing surface side of the main magnetic pole layer via a gap layer, 
 a backing coil layer formed on an area except the area between said main magnetic pole layer and said auxiliary magnetic pole layer, the backing coil layer having a coil surface parallel to a coil surface of a write coil layer, and 
 a backing coil-insulating layer which surrounds said backing coil layer; 
 
 said coil layer is the write coil layer which passes between said main magnetic pole layer and said auxiliary magnetic pole layer, the write coil layer generates a write magnetic field; and 
 said coil-insulating layer is a write coil-insulating layer which surrounds said write coil layer. 
 
     
     
       14. The head gimbal assembly as claimed in  claim 9 , wherein
 said magnetic coil element further includes
 a main magnetic pole layer, 
 an auxiliary magnetic pole layer having an end on an air bearing surface side opposed to an end on the air bearing surface side of the main magnetic pole layer via a gap layer, 
 a write coil layer passing between said main magnetic pole layer and said auxiliary magnetic pole layer, the write coil layer generates a write magnetic field, and 
 a write coil-insulating layer which surrounds said write coil layer; 
 
 said coil layer is a backing coil layer formed on an area except the area between said main magnetic pole layer and said auxiliary magnetic pole layer, the backing coil layer having a coil surface parallel to a coil surface of said write coil layer; and 
 said coil-insulating layer is a backing coil-insulating layer which surrounds said backing coil layer. 
 
     
     
       15. The head gimbal assembly as claimed in  claim 9 , wherein said thin-film magnetic head further comprises at least one heating portion for protruding an end on an air bearing surface side of said electromagnetic coil element toward a magnetic recording medium by a heat expansion. 
     
     
       16. The head gimbal assembly as claimed in  claim 15 , wherein said thin-film magnetic head further comprises a magnetoresistive effect element for reading data, said heating portion being set between said magnetoresistive effect element and said electromagnetic coil element. 
     
     
       17. A magnetic disk drive apparatus comprising:
 at least one head gimbal assembly including:
 a thin-film magnetic head including:
 an electromagnetic coil element for writing data including a coil layer which generates a magnetic field by current flowing through the coil layer and a coil-insulating layer which surrounds the coil layer; and 
 an overcoat layer which covers the electromagnetic coil element, 
 a width in a track-width direction of the coil-insulating layer being larger than a width that is a minimum width needed to insulate the whole coil layer, and being at least 46 μm, 
 a length in a direction perpendicular to the track-width direction of the coil-insulating layer being larger than a length that is a minimum length needed to insulate the whole coil layer, and being at least 75 μm, 
 a heat expansion coefficient of the coil-insulating layer being larger than or equal to 30×10 −6 /K, 
 a Young's modulus of the coil-insulating layer being larger than or equal to 1 GPa and smaller than or equal to 4 GPa, and 
 the length of the coil-insulating layer being greater than the width of the coil-insulating layer; and 
 
 
 a support mechanism for supporting said thin-film magnetic head; 
 at least one magnetic recording medium; 
 a recording/reproducing control circuit for controlling read and write operations of said thin-film magnetic head toward said at least one magnetic recording medium; and 
 a heating control circuit for controlling a heat operation of a heating portion in the case where said thin-film magnetic head includes said at least one heating portion. 
 
     
     
       18. A magnetic disk drive apparatus as claimed in  claim 17 , wherein said heat expansion coefficient of said coil-insulating layer is larger than or equal to 60×10 −6 /K. 
     
     
       19. A magnetic disk drive apparatus as claimed in  claim 17 , wherein said coil layer has a two layered structure, and said coil-insulating layer has a two layered structure. 
     
     
       20. A magnetic disk drive apparatus as claimed in  claim 17 , wherein
 said electromagnetic coil element further includes
 a lower magnetic pole layer, and 
 an upper magnetic pole layer which sandwiches a write gap layer with said lower magnetic pole layer on an end portion on an air bearing surface side; 
 
 said coil layer is a write coil layer passing between said lower magnetic pole layer and said upper magnetic pole layer, the write coil layer generates a write magnetic field; and 
 said coil-insulating layer is a write coil-insulating layer which surrounds said write coil layer. 
 
     
     
       21. A magnetic disk drive apparatus as claimed in  claim 17 , wherein
 said electromagnetic coil element further includes
 a main magnetic pole layer, 
 an auxiliary magnetic pole layer having an end on an air bearing surface side opposed to an end on the air bearing surface side of the main magnetic pole layer via a gap layer, 
 a backing coil layer formed on an area except the area between said main magnetic pole layer and said auxiliary magnetic pole layer, the backing coil layer having a coil surface parallel to a coil surface of a write coil layer, and 
 a backing coil-insulating layer which surrounds said backing coil layer; 
 
 said coil layer is the write coil layer which passes between said main magnetic pole layer and said auxiliary magnetic pole layer, the write coil layer generates a write magnetic field; and 
 said coil-insulating layer is a write coil-insulating layer which surrounds said write coil layer. 
 
     
     
       22. A magnetic disk drive apparatus as claimed in  claim 17 , wherein
 said electromagnetic coil element further includes
 a main magnetic pole layer, 
 an auxiliary magnetic pole layer having an end on an air bearing surface side opposed to an end on the air bearing surface side of the main magnetic pole layer via a gap layer, 
 a write coil layer passing between said main magnetic pole layer and said auxiliary magnetic pole layer, the write coil layer generates a write magnetic field, and 
 a write coil-insulating layer which surrounds said write coil layer; 
 
 said coil layer is a backing coil layer formed on an area except the area between said main magnetic pole layer and said auxiliary magnetic pole layer, the backing coil layer having a coil surface parallel to a coil surface of said write coil layer; and 
 said coil-insulating layer is a backing coil-insulating layer which surrounds said backing coil layer. 
 
     
     
       23. A magnetic disk drive apparatus as claimed in  claim 17 , wherein said thin-film magnetic head further comprises at least one heating portion for protruding an end on an air bearing surface side of said electromagnetic coil element toward a magnetic recording medium by a heat expansion. 
     
     
       24. A magnetic disk drive apparatus as claimed in  claim 23 , wherein said thin-film magnetic head further comprises a magnetoresistive effect element for reading data, said heating portion being set between said magnetoresistive effect element and said electromagnetic coil element.